Device for feeding sheets from one or two sources

Abstract

A device for feeding single sheets to a packaging, labelling or packeting machine, comprising a support structure provided with a table for positioning a stack of sheets to be fed, at least one pair of rotary drums arranged rigid with a drive shaft, and a plurality of operating elements associated with the pair of drums and comprising gripper elements positioned on the drums for gripping the sheets and sucker elements for withdrawing a single sheet from the bottom of said stack and transporting it towards the gripper elements. The drive shaft being divided into two parts which can be connected together in an intermediate region in a relative position rotated through any angle, a first linkage system comprising levers and cams being operationally associated with the operating elements of a first drum and a second similar linkage system being associated with the operating elements of a second drum, these being arranged on each of the two drive shaft parts.

We claim: 
     
       1. A feeding device for separately feeding single sheets from at least one stack of sheets, comprising: a support structure provided with a table for positioning a stack of sheets to be fed;   at least one pair of rotary drums rigidly positioned with a drive shaft which is rotatably supported on said support structure;   a plurality of operating elements associated with said pair of drums, said operating elements comprising gripper elements positioned on said rotary drums for gripping said sheets and sucker elements for withdrawing a single sheet from the bottom of said stack and transporting the single sheet towards said gripper elements; and   a linkage system comprising levers and cams provided in proximity to the first end of said drive shaft for controlling said operating elements so as to provide for a phase difference; wherein:   said drive shaft is divided into two parts which can be connected together in an intermediate region at ends of each of said parts, the ends of each of said parts being provided with removable engagement means and being capable of being secured in a relative position and rotated through any selectable angle;   said linkage system that comprises levers and cams operationally connected with the operating elements of a first drum of the device; and   a second linkage system comprising levers and came is provided in proximity to the other end of said drive shaft and is operationally connected with the operating elements of a second drum of the device.   
     
     
       2. A device as claimed in claim 1, wherein said engagement means consist of a first flat flange radially rigid with and projecting from one of said parts of said drive shaft, a second flange of larger dimensions keyed onto another of said drive shaft parts, and a backing flange mountable via a central hole onto said one drive shaft part and externally embracing said first flange, a surface of said backing flange acting by friction against the facing surface of said first flange with the aid of bolts insertable through respective holes provided in the flanges. 
     
     
       3. A device as claimed in claim 1, wherein said drive shaft can be connected at one end via a transmission to a central drive unit by way of a clutch element.